1999 C4 shifting issue

So only when my 911 is cold, for some reason on the first few shifts it does not like to shift into third gear. All the shift points are smooth and feel great. But for some reason third gear it doesnt want to go in. Kind of a pain in the ***. Now after a few minutes of driving as the car warms up the problem goes away. Its only 3rd gear. Now I asked my porsche mechanic and he said it may be the "gearbox" oil may need to be replaced. But when I look for videos on youtube when I type in "gearbox" oil replacement all that I mostly find is people changing the transmission fluid. IS that was he was referring to? OR is it something different then that? any help would be greatly appreciated. Thank you.

I had an issue in the past with 3rd gear being non receptive on occasion. First thought it was driver error but happened too many times for it to be a coincidence. Finally swapped shifter to a 997 Gt3 shifter and haven�t had an issue since. Best of luck.

mine does the same thing. also 3rd gear. not sure what causes it I've seen people say its from worn down synchros from not revmatching when downshifting to 3rd i made a habit out of putting the gear selector in 3rd a couple times with the clutch pedal in when the car is warming up. it seems to help a lot.

You mean just start the car and put in clutch and hold it down and slip into third and leave it for a bit?

Yep. Just in and out of third a couple times to kind of loosen it up. What I do is when I'm driving down my street in the morning in 2nd gear, i'll press the clutch pedal, move the gear selector to 3rd (without releasing the clutch) and back to second then release the clutch. ill do this a couple times as i'm driving out of my neighborhood, before I actually need 3rd. morning ritual.

When was the transmission/gearbox fluid last changed ? What fluid was used ? How many miles on the car ?

Mine used to be slightly difficult going into first gear when cold and it has an aftermarket short shift kit. Was fine one it warmed up. After putting on the Numeric, I don�t have the issue anymore, though I think in the most aggressive setup it can be a bit notchy. On the least aggressive and middle settings no issues whatsoever.

ill have to check the service records to see when it was last serviced. So the gearbox and transmission fluid are the same thing> the car has 144,000 miles on it

You didn't mention if you where in a cold weather town. But the gearbox can be a little "tough" here in chicago during the winter until it warms up. Once it's warm, no problems. I have owned my 2002 since 2002. And never messed with changing the shifter. One of these days I will. But next week I am going thru the exercise of changing my motor mounts. I have 57k miles on the car and was curios to see what new mounts will do for the shifting. I plan on changing the transmission mounts as well probably in April, after I see what/how everything feels with the new engine mounts. Eventually I will go with a numeric or cae shifter. But after 14 years of DE, the shifter still works fine in the warm weather months. but you do have to change the fluid from time to time as solid service.

I live in Arizona so pretty warm here year round.

One of the things you can do is make sure that all of your cables are in place. In addition to new motor mount , I am going to have my Indy make sure the cable are buttoned down properly. I haven't had any problems after 20 years but want to make sure,

Transmission fluid seems like a likely culprit In my case it almost feels like the gear selector gets hung up on the bearings or guides or whatever is in there. When going from 2nd to 3rd it almost feels like it gets caught between first and third. or on the "left" side of third gear. Hard to describe hopefully that makes sense. However I can report that running the selector in and out of third a couple times before driving completely solves the problem. Hasn't happened to me since I started doing this. But changing the transmission fluid might be the actual fix. I'll try it and report back. My car does it pretty reliably when it's cold and cannot replicate it soonafter.

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We had a few cold (for San Diego) days and I noticed mine felt a little heavy, but it seems to warm up to normal faster than the engine does. Generally, fluid is for an automatic, a much lower weight and formulated for planitary gears and the torque converter. I say "generally" because my Rubicon transfer case is gear/chain yet it still uses auto trans fluid. Gear oil is heavy. I changed mine a year ago, at 54k miles, to Delvac 75-90. At 144k miles you've done well if you are just a little sluggish when cold and it can only be a good thing to change it out. Since yours is a '99 do you have an LSD? if so check if it requires a friction modifier additive. At 54k miles I changed my engine mounts but noticed zero difference. The old ones had maybe 1/4" sag when I compared with the new ones. Even though my shifting was solid and I had no tailpipe sag I'd read a few threads saying to change them out due to age, but in my case it was a waste.

DSC, Yeah, at this stage, I am rotating thru parts replacement. I may be in the same boat as you with the engine mounts not feeling anything. Not only curious about shifting, but also curious on the track with balance. If there is an improvement, great! If not, then the mounts will be new, and one less thing to replace over the years. Same can be said for transmission mounts when I do it.

Yes, start with the cheap things first. Replacing the fluid is not a bad idea. Other possibilities are: 1. Shifter. The mechanism is plastic and there are better solutions. Function First makes something called Shift Right . 2. Shifter cables. These can stretch or the adjustment can be out of spec. On the GT3 they can be tough to replace. Don't know about the Carrera. 3. Transmission mount or possibly the engine mounts (or bothy). These sag with age. Engine is pretty easy. Transmission mount, not so much. 4. Worn synchronizers inside the gearbox. That's a more expensive proposition requiring a rebuild and then there is the "while you're in there" scenario (clutch, starter, slave cylinder...). At 144K miles you need to start thinking about anything rubber and plastic about the engine, too. So, if an engine drop is in your future, limber up your credit card because it is far cheaper to go through and slay all the dragons at once then waiting for them to start popping up one at a time.

I used the term " fluid " incorrectly sorry about that . The transmission takes gear oil . Porsche spec'd a very specific gear oil and it is a little pricey . By most accounts it performs the best . Some will use Swepco , some Red Line and many other brands have been used with varying degrees of success . If you change it yourself remove the fill plug FIRST . You don't want to be that guy that drains all the fluid out and then can't refill . At 144k this may or may not be an issue for you . With your mileage you are probably just seeing everything wear just a bit . The combination of all the items like synchro's/shift cables/shifter bushings etc all add up . I would start with a gear oil change and go from there .

i greatly apprecciate the insight thank you sir